#define _CRT_SECURE_NO_WARNINGS 1

//https://leetcode.cn/problems/remove-all-adjacent-duplicates-in-string/

class Solution {
public:
    string removeDuplicates(string s) {
        string ret;
        for (auto ch : s)
        {
            if (ret.size() && ch == ret.back()) ret.pop_back();
            else ret += ch;
        }
        return ret;
    }
};